github.com/murrekatt/go-ethereum@v1.5.8-0.20170123175102-fc52f2c007fb/core/gaspool.go (about)

     1  // Copyright 2015 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package core
    18  
    19  import "math/big"
    20  
    21  // GasPool tracks the amount of gas available during
    22  // execution of the transactions in a block.
    23  // The zero value is a pool with zero gas available.
    24  type GasPool big.Int
    25  
    26  // AddGas makes gas available for execution.
    27  func (gp *GasPool) AddGas(amount *big.Int) *GasPool {
    28  	i := (*big.Int)(gp)
    29  	i.Add(i, amount)
    30  	return gp
    31  }
    32  
    33  // SubGas deducts the given amount from the pool if enough gas is
    34  // available and returns an error otherwise.
    35  func (gp *GasPool) SubGas(amount *big.Int) error {
    36  	i := (*big.Int)(gp)
    37  	if i.Cmp(amount) < 0 {
    38  		return &GasLimitErr{Have: new(big.Int).Set(i), Want: amount}
    39  	}
    40  	i.Sub(i, amount)
    41  	return nil
    42  }
    43  
    44  func (gp *GasPool) String() string {
    45  	return (*big.Int)(gp).String()
    46  }